So, in looking at the picture, everyone was able to cue in on the fact that the elbows are down instead of up. This leads to a host of problems throughout the movement.
If, be it for flexibility reasons or just bad form, the elbows are down the first thing that will happen is a forward placement of the bar in front of the midline of the base of support, in this case Maggie’s foot. This forward placement will cause the weight of the barbell to be out front of the body, thereby taxing the midline as it tries to stay upright and over the center of gravity. This stress on the midline, the inability to keep the chest up, elbows up and the back in an upright and extended position, deforms the squat and predisposes the athlete to improper ROM, faulty movement patterns and potential injury. The lower back is taken out of extension and begins to round as the shoulder girdle softens, thereby collapsing under load. In compensation, the neck extends forward at an odd angle to maintain neutrality and the weight is borne onto the toes. The wrists are supporting a large majority of the load, the front delts are working overtime and upon coming up out of the hole, the knees are experiencing shear forces acting upon them by the extra loading of the quads and forward placement of the weight.
Insofar as depth is concerned, the squat should be ass to ankles. Although, as Tom pointed out, the front squat is less reliant upon the hamstrings due to the change in torso/pelvic angle, the stress on the knees can be relieved to some degree by some involvement of the adductors and hammies with a full depth squat. The majority of the work is going to be from the quads and if the weight is placed nicely over center foot, the drive will come off the heel allowing the knees and surrounding musculature to work together in an efficient and safe manner. Stopping high not only reduces the reflexive properties of the muscles experienced at full ROM, but limits the amount of weight you can move. The Stretch Shortening Cycle of the muscles and the natural hamstring/calf contact bounce is safe and effective with squats.
The pic on the right has a nice set up in it, besides being a tad high in the squat. The bar is over midfoot, the elbows are up and that places the neck in a natural extension and the back in a proper extension. There is still a lot of midline work going on to keep that bar over the foot as she drives up, but not nearly as much as when the bar is out front. The coaching cue here being to “drive the elbows up toward the ceiling”. This keeps the torso upright and lumbar and thoracic spine in nice extension and strong as hell.
I can’t see precisely where the knees are, but from the angle in the pic it would seem they are in a bit too narrow. A little more outward flare of the toes and subsequently the knees, would allow more depth into the bottom of the squat by allowing the hips to open more at the bottom. This again helps recruit more muscle into moving the weight back up and would allow even a tad more of a vertical torso position and better weight displacement.
Warm up drills with PVC bar or thumbs in the collar bone “elbow up/chest up” bottom of squat drills should induce a good stretch across the rear delts, triceps, and the mid back. It should almost feel as though the mid-back is about to cramp just below the shoulder blades. This is a good thing. Under load this tension will keep the spine happy and allow you to move heavy loads in the front squat.
In the case of poor flexibility, as in pic 1, all of the aforementioned problems are going to arise. So, if you have an athlete that is working on anterior chain development, you can have them work the front squat or transition them to a high bar “olympic style” back squat, keeping the torso as upright as possible. If front squats are your choice and the legs aren’t getting the work they should because the loading on the wrists and front delts prevent use of heavier weights then, and only then, can you do the stupid “cross your arms” front squat. Although I will ridicule you, you must still maintain the “elbows up/chest up” cues with this position to make the movement safe and effective.
So in order to get better at the front squat, you need to be flexible. Stretch not only the shoulders, but the lats and triceps, rhomboids and lower trapezius muscles in the back. Wrist felxibility helps to open the hand up and allow the elbows to come up since the hand is not “death gripping” the bar which puts tension in the forearm and reduces flexibility. Additionally, rolling out the back before and after workouts will help in developing the felxibility in the spine needed to maintain those upright and locked in positions.
There you have it, so go forth and conquer….or at least do some heavy front squats.